1. Field of the Invention
The present invention relates to the separation and identification of components of gas mixtures by chromatography, and more particularly to a new concept in the formulation of the stationary phase utilized in the chromatographic column.
2. Description of the Prior Art
Mixtures of gases have been separated by various means including chromatography on a column packed with various polymers or molecular sieves. The packing material may be microporous and/or may consist of microsphere or other fine particulate structures. Thus, mixtures of nitrogen, carbon monoxide, carbon dioxide, hydrogen, water vapor, and hydrocarbon gases have been separated successfully with a microporous crosslinked polymer made of about 80% monovinyl monomer and 20% divinyl monomer (U.S. Pat. No. 3,650,090). A stream of gaseous hydrocarbons can be analyzed by means of a column of glass beads covered by a polymeric film deposited in situ, said film being composed of the usual divinyl and monovinyl monomer ratio (U.S. Pat. No. 3,822,530). In any event, while it is possible to obtain separation of oxygen from nitrogen in an atmospheric mixture of gases with certain porous carbon molecular sieves, long columns and long processing times are needed to isolate oxygen in the presence of argon.
The separation of oxygen from other gases has also been attempted with the help of chelates. For example, it has been found that cobalt salicylaldehydeethylenediamine dissolved in pyridine or packed in a column with inert material can separate oxygen from air by absorption at cool temperatures and desorption at 100.degree. C. (U.S. Pat. No. 2,508,490). N,N'-ethylenebis(acetylacetoniminato)-cobalt (II), i.e., Co(acacen), when placed in a coordinating solvent such as dimethyl formamide or in a noncoordinating solvent such as toluene with a base like pyridine, will slowly absorb oxygen over a period of days. At temperatures near or lower than 0.degree. C., a rapid and reversible uptake of dioxygen has been observed [Basolo et al., Accounts of Chem. Res. 8, 384-392 (1975)].
Finally, certain transition metal complexes such as diethylpyridyl nickel have been recently combined with, for example, halogenated styrene-divinyl benzene copolymer (U.S. Pat. No. 3,933,770). The resulting metal-polymer complex served, in that instance, to catalyze the dimerization of ethylene to butene.
An object of the present invention is to provide a new type of chromatographic column packing material which can simplify and improve the separation of atmospheric gases in terms of time, quantity of material needed and sharpness of separation. Another object is to devise chromatographic processes which will separate various common mixtures of oxygen and carbon monoxide in nitrogen, a separation that has been difficult heretofore. A further object is to devise methods for the manufacture of the chelate-polymer complexes of the invention which insure that said complexes have the proper steric configuration that is necessary to achieve the desired degree of absorption and desorption of gases.